Engine choke



Aug. 29, 1939. w. s. ROBERTS 2,171,008

ENGINE CHOKE Filed Nov; 28, 1938 2 Sheets-Sheet l 7'0 IGNITION In venior mill am 5'. FaZerZ-s A iiomeys Aug. 29, 1939. w 5 ROBERTS 2,171,008

ENGINE CHOKE Filed Nov. 28, 1938 2 Sheets-Sheet 2 4/ I In venior il zzll am S )EaJerZs By M A tiorneys Patented Aug. 29, 1939 UNITED STATES PATENT OFFICE 3 Claims.

This invention relates to internal combustion engines and more particularly to a choke therefor.

An object of the present'invention is to provide for the automatic choking of an internal combustion engine incidental to the starting of the motor; and the invention together with its objects and advantages will be best understood from a study of the following description taken in connection with the accompanying drawings wherein:

Figure 1 is a view somewhat diagrammatically illustrating the application of the invention.

Figure 2 is a detail elevational view illustrating certain details hereinafter more fully referred to.

Figure 3 is a sectional view through a suctionresponsive make and break device, and

Figure 4 is a perspective View of a rocker shaft hereinafter more fully referred to.

Referring more in detail to the drawings it will be seen that in accordance with the present invention the starter switch 5 has the pivoted contact 6 thereof normally biased out of engagement with the stationary contacts of the switch through the medium of a spring I. The pivoted bar 8 carrying the contact 6 is provided with an armature 9 complemental to an electro-magnet ID the ground for which is indicated at H.

One of the stationary contacts, namely the contact l2, of the starter switch is connected with one side of a starter motor 13 through the medium of a wire 14. The other of the stationary contacts, namely the contact I5 of the switch 5 is connected through the medium of a wire 16 with one side of a battery E7. The ground for the battery I! is indicated at l8. Also, and as shown in Figure 1, the contact 15 of the switch 5 is connected with the ignition switch H! of the automobile through the medium of a wire 20.

The switch l3 has a stationary contact 2| from which leads a 32 to the ignition; and a stationary contact 23 from which leads a wire 24 that is connected as at 25 to a stationary contact 26 of a suction-responsive make and break device indicated generally by the reference numeral 21.

The make and break 27 comprises, as best shown in Figure 3, a cylinder 28 which adjacent one end thereof is connected with the intake manifold 25 of the internal combustion engine 30 through the medium of a pipe or conduit 3 I.

The aforementioned contact is arranged within one end of the cylinder 28 and having a sliding fit within the cylinder 28 is a piston 32 of conductive material. Carried by the piston 32 and complemental to the contact 26 is contact 33.

Threaded in end the cylinder 28 is a plug 33 of dielectric material and extending through the plug 34 is a terminal post 35 to which is suitably connected one end of a wire 36 that leads from the electro-magnet l0.

Interposed between the plug 34 and the piston 32, within the cylinder 28, is a coil spring 3! that normally acts on the piston 32 to urge the same in a direction engaging contact 33 with contact 28.

The ground for the starter motor i3 is indicated at 38.

From the description thus far it will be seen that when the ignition switch I9 is closed the circuit is completed through the battery ll, motor l3, make and break device 21, and electromagnet l0. When the magnet I0 is thus energized armature 9 is attracted thereby causing a closing of the switch 5 and the completion of the circuit through the starting motor l3 resulting in a starting up of the engine 30.

With the engine 30 running the exhaust gases will build up a pressure acting on the piston 32 in opposition to the spring 3'! for moving contact 33 out of engagement with contact 26 thus interrupting the circuit through the coil l0 so that the switch-carrying arm 8 will, in response to spring I, move to the position shown in Figure 1 for interrupting the circuit through the starting motor.

Further in accordance with the present invention I provide a substantially U-shaped member 39 that at the closed end of the U is provided with a lateral lug 40 through the medium of which the U-shaped member is secured to the ends of a band 4| clamped about the motor housing or casing of motor 13 through the medium of bolt and nut means 42.

Pivoted to one arm 43, as at 44, is a pitman rod 45 that is provided in the free end thereof with a slot 46 that receives an eccentric pin carried by a crank disk 48 on one end of the shaft of the motor l3.

Also pivoted to the arm 43 of the U-shaped member 39, as at 49, is one end of a bar Pivotally and adjustably connected to the free end of the bar 50, as at 52, is a link that at its upper end is pivoted to an arm of a bell crank 66 hereinafter more fully referred to.

A rock shaft as shown in Figure 1 is journaled in a pair of supporting standards 58 mounted on and rising from the head of the motor The shaft 55 is also provided with an arm 57 that is connected through the medium of a link 58 with a temperature responsive element mounted on the exhaust manifold 20 of the internal combustion engine as shown in Figure 1.

For the free end of the bar 55 there is mounted on the arm 60 of the U-shaped member 39 a stop 6| as shown in Figure 2.

Also pivotally mounted on the arm of the U-shaped member 39 is a bell crank 6i. Bell crank 6| has one arm thereof connected through the medium Of a link 62 with a member 63 pivoted at one end thereof to an intermediate portion of the bar 50 as at 64. The free end of the member 63 is arranged in the path of the crank 15 as shown in Figure 2.

The other arm of the bell crank 6| is pivotally connected through the medium of a link 65 with one end of an arm 54 also provided on the aforementioned shaft 55.

The other arm of the aforementioned bell crank 66 is connected through the medium of a link 6'5 with the crank arm 68 of the choke valve 69 of the internal combustion engine.

The choking operation may now be briefly explained as follows:

In starting a cold motor the operator turns on the ignition switch in the usual manner thus completing, as hereinbefore explained, the ignition circuit and the battery circuit embodying the magnetic coil or electro-magnet IE whereupon switch 5 is closed and the starting motor I3 set into operation for starting the internal combustion engine 30. Obviously as the shaft of the motor [3 revolves the crank or eccentric member 45 will be caused to oscillate and this oscillatory movement of the crank 45 will be transmitted through the medium of the member 63, pivoted to the bar 58, for causing the latter to rapidly alternately raise and lower on its pivot 49. This movement of the bar 5!) is transmitted through the medium of the link 53, bell crank 66, and link 61 to the crank arm of the choke valve 69 causing the latter to rapidly alternately open and close resulting in the wellknown choking operation, often resorted to by the operator in starting a cold motor.

As the motor 30 warms up the exhaust gases from the motor will act, in a manner hereinbefore explained, on the circuit make and break device 21 for separating the contacts 26 and 33 thus interrupting the circuit through the magnet I causing the latter to become de-energized. Upon such de-energization of the magnet H] the lever B swings in response to the spring I to open the switch and thus. interrupt the circuit to the starting motor l3 for cutting out this motor after the engine 3!] has started.

Also, as the engine 30 warms up, the thermal element 59 will be affected by the hot gases flowing through the exhaust manifold 29 and will contract thus causing the shaft 55 to rock in a direction exerting an upward pull on the link 65. As link 65 moves upwardly the member 63 is. pulled or swung to the dotted line position shown in Figure 2 out of the path of the crank member 45 and will remain in this dotted line position as long as the motor remains warm. Consequently it will be seen that when subsequently starting the warm motor, the choking operation, hereinbefore described in detail, will not be repeated, and of course this is desirable since in starting a Warm motor such choking operation is not ordinarily necessary or resorted to.

It is thought that a clear understanding of the construction, utility and advantages of an invention of this character will be had without a more detailed description thereof.

Having thus described the invention what is claimed as new is:

1. In combination with an internal combustion engine having an exhaust manifold, a choke valve, a starter motor, a control switch for the starter motor, and an ignition switch, of electromagnetic means operable to close the starter switch incidental to a closing of the ignition switch, a normally closed circuit make and break device connected with the exhaust manifold for operating in response to the pressure of exhaust gases for interrupting the circuit to the electromagnetic means after the internal combustion engine has been set in operation, means connected with the starting motor and the choke valve for transmitting drive from the starting motor to the choke valve for operating the latter while the starting motor is in operation, a temperature responsive device mounted on a part of the engine and means actuated thereby, when the same has been acted upon by the heat from the engine, for rendering the choke valve operating means inactive.

2. In combination with an internal combustion engine having an exhaust manifold, a choke valve, a starter motor, a control switch for the starter motor, and an ignition switch of electromagnetic means operable to close the starter switch incidental to a closing of the ignition switch, a normally closed circuit make and break device connected with the exhaust manifold for operating in response to the pressure of exhaust gases for interrupting the circuit to the electromagnetic means after the internal combustion engine has been set in operation, means connected with the starting motor and the choke valve for transmitting drive from the starting motor to the choke valve for operating the latter while the starting motor is in operation, a temperature responsive device mounted on the exhaust manifold of the internal combustion engine, and means operatively connected with said temperature-responsive device and the aforementioned drivetransmitting means connected with the starting motor and the choke valve for maintaining the drive from the starting motor to the choke Valve interrupted while the motor, is warm.

3. In combination with an internal combustion engine having a choke valve, an exhaust manifold, and a starter motor for the engine, a supporting structure mounted on the starting motor, a pitman member pivoted at one end thereof to said supporting structure and having an eccentric drive connection with the shaft of the starting motor, a bar pivoted to said supporting structure, a member pivoted to said bar and normally arranged in the path of said pitman rod for transmitting movement of the pitman rod to said bar, link means operatively connecting said bar with said choke valve for transmitting movement of the bar to the choke valve for operating the latter, a bell crank pivoted to said supporting structure, link means operatively connecting the bell crank with the aforementioned member pivoted to the bar for moving said pivoted member out of the path of said pitman rod, a temperatureresponsive device mounted on the exhaust manifold, and means operatively connecting said temperature-responsive device with the aforementioned bell crank whereby when the internal combustion engine is warmed up said pivoted member will be caused to move out of the path of said pitman rod and will be retained out of the path of the pitman rod as long as the internal combustion engine remains warm, as and for the purpose specified.

WILLIAM S. ROBERTS. 

